Nephrosclerosis in young patients with malignant hypertension.

Nephrosclerosis is one of the histopathological consequences of severe or malignant hypertension (MH), some of the pathophysiology for which has been extrapolated from essential polygenetic arterial hypertension. Despite our recent description of unsuspected ciliopathies with MH, causes of MH in young patients with severe renal impairment are poorly understood. To refine and better describe the MH phenotype, we studied clinical and prognostic factors in young patients receiving a kidney biopsy following their first episode of MH. Patients were identified retrospectively and prospectively from eight centers over a 35-year period (1985-2020). Key words were used to retrospectively enrol patients irrespective of lesions found on renal biopsy. 114 patients were included, 77 (67%) of whom were men, average age 34 years, 35% Caucasian, and 34% African origin. Isolated clinical diagnosis of severe nephrosclerosis was suggested in only 52% of cases, with 24% primary glomerulopathies. Only 7% of patients had normal renal function at diagnosis, 25% required emergency dialysis and 21% were eventually transplanted. Mortality was 1% at last follow-up. Independent prognostic factors significantly associated with renal prognosis (6-month dialysis) and predictive of end-stage renal disease were serum creatinine on admission (OR = 1.56, 95% CI: [1.34-1.96], p < 0.001) and renal fibrosis > 30% (10.70, [1.53-112.03], p = 0.03). Astonishingly, the presence of any thrombotic microangiopathy lesion on renal biopsy was an independent, protective factor (0.14 [0.02-0.60], p = 0.01). The histopathological hallmark of nephrosclerosis was found alone in only 52% of study patients, regardless of ethnicity. This suggests that kidney biopsy might be beneficial in young patients with MH.